Institute of Microwaves and Photonics

The terahertz (THz) region of the electromagnetic spectrum, spans the frequency range between the mid infra-red and the millimetre/microwave (300 GHz – 30 THz). This region of the spectrum has yet to be properly exploited owing to the severely limited number of sources and detectors available. There has therefore been considerable interest in the production of radiation sources which emit in the THz region of the electromagnetic spectrum. Over the last ten years or so, terahertz science and technology has advanced considerably with both optical-bench-based systems and solid state THz lasers (quantum cascade lasers) now routinely available.

A selection of the research programmes that we are currently carrying out is listed here. The research is supported by the Research Councils UK, the EPSRC, the EC, as well as other institutions such as Her Majesty's Government Communication Centre (HMGCC) ) and the Defence Science Technology Laboratory (DSTL).

• The development of THz quantum cascade lasers, including their design, growth, fabrication and measurement.
• The development of THz quantum cascade laser based imaging and spectroscopy systems.
• The use of broadband THz frequency radiation to study low-dimensional semiconductor structures, nanostructures, and other condensed matter systems.
• The development of on-chip, guided-wave, THz filter systems to investigate, inter alia, biological systems such as DNA.
• The use of broadband THz systems to understand the fundamental interactions of THz radiation with materials of security interest, such as drugs-of-abuse and explosives.
• THz spectroscopy of flames, ceramics and glasses.
• Measurement of water content of foods.
• The development of superlattice electron device (SLED) and two-colour laser CW THz sources.

We also coordinate the €5M, FP6 IST TeraNova programme which is co-ordinated at Leeds. Further information can be found at: www.teranova-ist.org.

Facilities:
Our recently refurbished, 160 square metre terahertz photonics laboratory has accommodation for eight optical bench systems within a positive-pressure, temperature controlled environment. An isolated area with wet bench and fume extraction facilities is provided for sample preparation. This state-of-the-art laboratory, funded in part by a Royal Society Wolfson Foundation Laboratory Refurbishment award and in part by SRIF II funding from the University, is probably the largest university facility of its kind in Europe. 

At present, our capabilities include the following:
• Five fs pulsed imaging and spectroscopy systems, including ultra-broadband capability (>20 THz), pump-probe techniques, and evacuated systems;
• Fourier transform infrared spectroscopy for characterization of QCL devices;
• 1.2 K optical access cryostats (bath and continuous flow) for low temperature measurements and QCL operation.

Furthermore, this laboratory is supported by a new III-V MBE growth system and extensive semiconductor processing facilities.

For more information, contact Professor Giles Davies, Professor Edmund Linfield, Professor John Cunningham.